在来自不同控制器的函数中使用两个变量

Question

I have a function in which I want to use a variable from a different view controller and a variable defined within the function. The variable from the different view controller is being sent to the second view controller with the following code:

func clock(){

    time++

NSNotificationCenter.defaultCenter().postNotificationName("timerValID", object: time)

}


@IBAction func TimerGo(sender: AnyObject) {


    timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: ("clock"), userInfo: nil, repeats: true)


}

The code from the second view controller (function containing two variables) is:

override func viewDidLoad() {
    NSNotificationCenter.defaultCenter().addObserver(self, selector: Selector("location:"), name: "timerValID", object: self.view.window)}


func location(manager: CLLocationManager, didUpdateLocations locations: [AnyObject]!)(notification: NSNotification){

    var startlocation: CLLocation!
    var lastlocation: CLLocation!
    var traveleddistance: Double = 0
    var speed:CLLocationSpeed = CLLocationSpeed()
    let time = notification.object as! NSNumber

}

When I run the app, I get the message: Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: unrecognized selector sent to instance.....

Answer 1

The important part of the error is the part you missed and replaced with ".....". It would tell you which selector was the problem.

Nevertheless, looking at your code, there are a couple of problems.

Firstly, with Swift, you don't use Selector("myFunc") , you just use "myFunc". Also, the "object:" parameter is the source of the notification. In most cases you will use "nil" for "any source of this message". So therefore you would have

     override func viewDidLoad() {
         NSNotificationCenter.defaultCenter().addObserver(self, 
             selector: "location:", name: "timerValID", object: nil)
     }

Secondly, your addObserver function will be passed just one object, which is the notification. Therefore, the signature for "location:" should be

    func location(notification: NSNotification){     
        //do stuff
    }

This is probably the cause of the error you are seeing, because you don't have a method with the expected signature.